The present invention relates to an amplifier circuit and a gain control method thereof.
Radio communication devices such as mobile phones are provided with variable gain amplifiers that adaptively vary gain (output voltage/input voltage) according to control signals Such a variable gain amplifier generates an output voltage of a desired voltage level by amplifying an input voltage while controlling gain according to a supplied control signal.
A name of a reference document on variable gain amplifiers will be provided below
Japanese Patent Laid-Open No. H9-321577